Effects of interlayer notch and shear stress on interlayer strength of 3D printed cement paste

Abstract

In this paper for investigation of the effect of interlayer notch and shear stress on interlayer strength of 3D printed cement paste, experimental work is conducted with emphasis on the effects of nozzle shape, nozzle height and printing speed on the interlayer strength. It is observed experimentally that the cement paste printed by the circular nozzle generally achieves a higher interlayer strength, compared with that printed by the rectangular nozzle. A smaller nozzle height may impair the interlayer strength if the interlayer notch is not treated properly. In addition, a higher printing speed marginally increases the interlayer strength, showing the promise of a higher productivity. Theoretically, the experimental phenomena are innovatively explained by the interlayer notch coupled with shear stress on the contact surface, through finite-element and computational-fluid-dynamics simulations. Therefore, reducing the interlayer notch and increasing the interlayer shear stress become crucial in the cement paste for 3D printing process.